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Anthropomorphic Phantoms Analytical and voxel models Status and perspectives. Giorgio Guerrieri July 13 th , 2005. Mathematical phantoms The size and shape of the body and its organs are described by mathematical expressions representing combinations and intersections of planes,
The size and shape of the body
and its organs are described
by mathematical expressions
representing combinations and
intersections of planes,
circular and elliptical cylinders
spheres, cones, tori, …
Based on digital images
from scanning of real persons
by computer tomography (CT)
magnetic resonance imaging
NRPB Mathematical Phantom
(National Radiological Protection Board)
(MRI data of a volunteer)
(Medical Internal Radiation Dose Committee, pamphlet no 5)
(from CT and MRI data)
(Oak Ridge National Laboratory)
Missing in Geant4
Already developed by other group using Geant4, not publicA wide panorama of phantoms
2005, April: Monte Carlo Topical Meeting, Tennessee
In the session about “Tomographic Models for Radiation Protection Dosimetry”,
many talks about anthropomorphic phantom (mainly voxel-based models) have been presented:
- GSF Male And Female Adult Voxel Models Representing ICRP Reference Man By Keith Eckerman
- Effective Dose Ratios For The Tomographic Max And Fax Phantoms By Richard Kramer
- Reference Korean Human Models: Past, Present and Future By Choonsik Lee
- The UF Family of Paediatric Tomographic Models By Wesley Bolch and Choonik Lee
- Development And Anatomical Details Of Japanese Adult Male/ Female Voxel Models By T. Nagaoka
- Dose Calculation Using Japanese Voxel Phantoms For Diverse Exposures By Kimiaki Saito
- Stylized Versus Tomographic Models: An Experience On Anatomical Modelling At RPI By X. George Xu
- Use Of MCNP With Voxel-Based Image Data For Internal Dosimetry Applications By Michael Stabin
- Application Of Voxel Phantoms For Internal Dosimetry At IRSN Using A Dedicated Computational Tool
By Isabelle Aubineay-Laniece
- The Use Of Voxel-Based Human Phantoms In FLUKA By Larry Pinsky
- The Future Of Tomographic Modelling In Radiation Protection And Medicine (Panel discussion)
In particular for applications in radiation shielding of habitats
for astronauts, such as transfer vehicles and surface habitats
for future manned exploration missions.
The development of anthropomorphic phantoms, together with Geant4 physics
modelling, makes possible to study the radiation damage to the astronauts' organs during interplanetary missions.
Anthropomorphic Phantoms for Geant4 toolkit
The project for Geant4 toolkit is addressed to develop anthropomorphic phantom that can beentirelycustomized by the user.
As in URD, the user shall be able to:
- Choose model for each body part to add to the phantom (ORNL, MIRD)
- Add single voxel-based body part from DICOM file (CT, MRI)
First attempts to model the shape of a human being and its internal organs in order to calculate absorbed radiation doses were made by Snyder et al. (1969) and Koblinger (1972).
These were based on the anthropomorphic MIRD-type phantom, which was originally developed for the dosimetry of internal radionuclide sources.
The Medical Internal Radiation Dose Committee creates MIRD5
that has been the basis for various derivations, like the ORNL Mathematical Phantom Series.
W. S. Snyder, M. R. Ford, G. G. Warner, H. L. Fisher jr
MIRD Pamphlet # 5 Revised: “Estimates of absorbed fraction for monoenergetic photon sources uniformly distributed in various organs of a heterogeneous phantom”, J Nucl Med Suppl 3, 1969.
K. F. Eckerman, M. Cristy, J. C. Ryman
“The ORNL Mathematical Phantom Series”, http://homer.ornl.gov/vlab/VLabPhan.htmlAnalytical Model
The anatomies of new-born, and children of age 1 year, 5 year, 10 year, 15 year and adult male and female had been modelled at the Oak Ridge National Laboratory by Cristy and Eckerman (1987).
Trunk, neck, head, legs, male genitalia, breasts
Skeletal systemLeg bones, arm bones, pelvis, spine, skull, rib cage, clavicles, scapulae
Gastrointestinal tract and contentsEsophagus (thoracic + abdominal portions),stomach (wall + contents), small intestine, upper large intestine (ascending colon wall and contents, transverse colon wall and contents), lower large intestine (descending colon wall and contents, lower large sigmoid colon wall and contents)
Heart and contents
Outer surface of heart, left ventricle (wall + contents), right ventricle (wall + contents),
left atrium (wall + contents), right atrium (wall + contents), heart (wall + contents)
Adrenals, brain, gall bladder (wall + contents), kidney, liver, lung,ovary, pancreas, spleen, testes, thymus, lobes of thyroid, urinary bladder (wall + contents), uterusAnthropomorphic Phantom: URD (1)
- The goal of the project is the development of a Geant4 package addressed to the modelingof an anthropomorphic phantom providing a realistic description of the human body and anatomy.
- The phantom consists of a mathematical model of:
Elemental composition of tissues:
The Abstract Factory
provides an interface
for creating families
of related object
their concrete classes.
It makes exchanging
product families easy.
It can use different product
by changing the concrete factory.
The creational pattern Builder separates the construction of a complex object from its representation
so that the same construction process can create different representations.
The Builder object provides the director
with an abstract interface for constructing
Thanks to the abstract interface
all one has to do to change the product's
internal representation is define
a new kind of builder.
Unlike creational patterns that construct
products in one shot,
the Builder pattern constructs the product
step by step under the director's control.
In both ORNL and MIRD mathematical phantoms most of the organs can be easily approximated
with solids or part of them that currently are not implemented in the Geant4 Geometry Package:
Geant4 functionality has to be extended, developing the software to describe the ellipsoid
Design of the new
and part of it are used to describe several organs like stomach, ovaries, brain, or lungs and kidneys...
This test consisted of 1D-flux of geantinos with direction parallel to X axis impinging onto an ellipsoid.
The ellipsoid has semi-axis lengths: a = 7. µm , b = 10. µm, c = 15. µm.
The solid is spaced in an enclosed box volume defined world which sizes are 40.µm.
The number of events generated in the test is 10^4.
The same test was performed for 1D-beams with direction parallel to Y and Z directions.
The path length of the geantinos was verified to be equal to the sizes of the ellipsoid, as expected.
This test consisted of an isotropic flux of geantinos impinging onto an ellipsoid.
The ellipsoid has semi-axis lengths: a = 7. µm, b = 10. µm, c = 15. µm.
The solid is spaced in an enclosed box volume defined world which sizes are 40 µm.
The number of the events generated in the test is 5 ·10^5.
Projection on plane XY, YZ, ZX
The software implementing the ellipsoid has been included in
Geant4 CVS repository in Geometry/solids/specifics.
This work will be documented by an INFN pre-print (in progress)G4Ellipsoid
The new class G4Ellipsoid
is meant to be publicly available
in the next Geant4 release.
- general trapezoid
- elements built from
- complex materials
- mixtures built from
elements and/or other
by fractional mass
Actual definitions of
- Cartesian position and
rotationGDML Geometry Description Markup Language
The Geometry Description Markup Language work-package is meant to provide geometry data exchange format for the LCG applications.
The work-package consists of the GDML Schema part, which is a fully self-consistent definition of the GDML syntax, and the GDML I/O part, which provides means for writing out and reading in GDML files.
What users gain is the reduced time when writing their geometry description as no need for re-compilation and re-linking of their applications is required even for one number change.
The other advantage is that it allows them easy exchange of geometry data without a need to reveal their source code and makes life easier for developers as well because they can use the GDML data for tracing bugs and problems in geometry processing code.
The GDML work-package can be useful for simplify geometry description of body parts
The GDML work-package read out geometries implemented in Geant4. If other solids will be implemented (the ellipsoid...) in the Geant4 Geometry Package, the GDML Processor is to be extended with them.
and the GDML Processor is now able to draw ellipsoid.
The next official GDML distribution will have
the extension to read the new solid
(once the G4Ellipsoid is available in G4 release)
The GDML package has been extended
to create volumes parametrized for the elliptical tube.
an anthropomorphic phantom example
We have explored GDML functionality for a preliminary implementation
of an example of an analytical anthropomorphic phantom.
Elements of “Human phantom” example:
Primary particle can be originated in different conditions
- The user can choose the type of particle
- The user can originate beam with defined energy and initial direction
- The user can originate particle from a sphere (isotropic flux)
GDML file is created by the user, through User Interface.
- The user can choose phantom by sex (Male or Female)
- The user can choose phantom by model (ORNL, MIRD or MIX)
- The user can choose which body part is to be built
- The user can set sensitivity for each body part
Materials are defined in GDML file
There are three materials defined for different body parts:
- Skeleton: for the parts of skeleton system
- Lung: for the lungs
- Soft Tissue: for all other body part
These are defined by their elemental composition and densities.
In body part volume the energy deposit is collected
The energy deposit is given by the primary particles
and all the secondaries generated.
Sensitive Body Part
- Visualizations (OPENGL, VRML, DAWN)
- Primary Particles in term of initial energy and direction
- Geometry set-up
<gdml xmlns:gdml="http://cern.ch/2001/Schemas/GDML" ...
<volume name="BreastsVolume" >
<materialref ref="SoftTissue" />
<solidref ref=”BreastsVolume” />
<volume name="BodyVolume" >
<materialref ref="SoftTissue" />
<solidref ref="Body" />
<volumeref ref="BrainORNLVolume" />
<positionref ref="BrainORNLPos" />
<rotationref ref="BrainORNLRot" />
Through macro file adultFemale.mac
# Initialize Phantom
# Define Sex
# Define Model
# Body part and Sensitivity
/bodypart/addBodyPart Stomach yes
/bodypart/addBodyPart Spleen no
/bodypart/addBodyPart Brain yes
# Finalize GDML file
GDML file is processed by GDML Processor
and the user phantom is built...
Example of geometry setup
Upper Large Intestine
Lower Large Intestine
Not visible: Brain (in the skull)
TrackID: 2 -> LegBonesORNLVolume -> Energy deposit: 3.4576726 MeV
TrackID: 2 -> BodyVolume -> Energy deposit: 5.1323606 MeV
TrackID: 2 -> BodyVolume -> Energy deposit: 5.1711365 MeV
TrackID: 2 -> BodyVolume -> Energy deposit: 701.06096 keV
TrackID: 16 -> BodyVolume -> Energy deposit: 807.59738 keV
TrackID: 23 -> BodyVolume -> Energy deposit: 1.497982 keV
TrackID: 22 -> BodyVolume -> Energy deposit: 2.3391091 keV
TrackID: 21 -> BodyVolume -> Energy deposit: 220.25512 eV
TrackID: 20 -> BodyVolume -> Energy deposit: 10.468365 keV
TrackID: 19 -> LegBonesORNLVolume -> Energy deposit: 16.651015 keV
TrackID: 24 -> BodyVolume -> Energy deposit: 4.0614721 keV
Female ORNL Anthropomorphic Phantom> Run 1 <
Energy: 100. MeV
no. Particle: 20
Beam Direction: along Z axis
Visualization system: OpenGL
Output of run 1
TrackID: 34 -> ArmBonesORNLVolume -> Energy deposit: 70.168538 keV
TrackID: 33 -> BodyVolume -> Energy deposit: 19.493675 keV
TrackID: 32 -> BodyVolume -> Energy deposit: 42.318809 keV
TrackID: 31 -> SpleenORNLVolume -> Energy deposit: 119.96815 keV
TrackID: 30 -> SpleenORNLVolume -> Energy deposit: 3.9230135 MeV
TrackID: 29 -> PancreasORNLVolume -> Energy deposit: 1.0284905 MeV
TrackID: 18 -> BodyVolume -> Energy deposit: 543.1 eV
TrackID: 37 -> BodyVolume -> Energy deposit: 33.841459 keV
TrackID: 36 -> LiverORNLVolume -> Energy deposit: 986.16275 eV
TrackID: 35 -> LiverORNLVolume -> Energy deposit: 1.9230902 keV
Female ORNL Anthropomorphic Phantom> Run 2 <
Energy: 100. MeV
no. Particle: 20
Beam Direction: along X axis
Visualization system: OpenGL
Output of run 2
has been created for Geant4 simulation toolkitConclusions